A typical axial flow, industrial gas turbine engine has a compression section, a combustion section, and a turbine section. An annular flowpath for working medium gases extends axially through the sections of the engine.
At the inlet to the compression section, the gases are primarily air. As the working medium gases are flowed along the flowpath, the gases are compressed in the compression section causing the temperature and the pressure of the gases to rise. The temperature of the gases exiting the compression section may exceed eight-hundred
The hot, pressurized gases are flowed from the compression section to the combustion section. In the combustion section, the gases are mixed with fuel and are burned to add energy to the gases. These heated, high energy gases are expanded through the turbine section to produce useful work, such as by driving a turbine rotor that powers the compressor and by driving a second (or free) turbine which may be drivingly connected to a pump or electrical generator.
The combustion section includes one or more combustion chambers and a plurality of fuel injectors for supplying air and fuel to the combustion chambers. One example of a fuel injector is described in U.S. Pat. No. 4,377,618 which shows fuel discharged into an airstream so that mixing of the fuel and air takes place within an inner chamber. An annular second passage 68 outwardly of a first passage 62 provides a flowpath for air and water. A gaseous fuel is flowed through a third passage 44, 46 which is disposed radially outwardly of the first two passages.
Another example of a fuel injector is shown in U.S. Pat. No. 4,977,740 issued to Madden, Schlein, who is a co-inventor of the subject application and Wagner. U.S. Pat. No. 4,977,740 is assigned to the assignee of this application. In U.S. Pat. No. 4,977,740, two radially spaced passages form swirling columns of air. A liquid fluid passage is disposed between the air passages for injecting liquid fuel or water between the swirling airstreams. A gaseous fuel passage 116 is outwardly of the outermost air passage and provides for the independent injection of gaseous fuel or steam into the combustion zone downstream of the combustion chamber.
The above art notwithstanding, scientists and engineers are working under the direction of applicants assignee to further improve fuel injector assemblies, particularly of the type shown in U.S. Pat. No. 4,977,740 the material of which is incorporated herein by reference.